By comparison (since I was curious), 70 hours on an m3.medium spot instance will run around $0.70. On an on-demand, it's about $5.39. EMR will cost you about $7.00 on top of the EC2 costs.
If you can peg the CPU and don't mind getting interrupted, spot instances are still a fair bit cheaper. But Lambda looks pretty attractive for any other use-case where the statelessness of Lambda doesn't bite you.
Keep in mind that with EC2 you're billed hourly so the fastest a 70 cpu-hour job could finish on m3.medium for $0.70 is 1 hour, and that's ignoring setup time, etc.
Meanwhile, on Lambda, you can actually run 1600 60s jobs (or 27 CPU-hours) in 3 minutes. This is inclusive of setup time, job submission, stragglers, etc. [1]
Of course, if you've got sustained load, it's cheaper to go with spot instances, but the "occasionally I need a buttload of compute," model is well-served by Lambda.
I personally often want to run a bunch of things for ~1-15 minutes, and have too much data or setup to fit neatly in a lambda function. However, I don't need 1000 things running simultaneously, although manta would help still there.
I'd love to see some more layers over the top of services like this, hopefully someday getting us back to picloud. I miss that service.
How secure are docker hosts like hyper.sh? I've always been skeptical, the multitenant docker security story hasn't been very encouraging, or has that changed?
If you can peg the CPU and don't mind getting interrupted, spot instances are still a fair bit cheaper. But Lambda looks pretty attractive for any other use-case where the statelessness of Lambda doesn't bite you.